Electric power generators are well-established devices in which mechanical energy is converted to electrical energy through the magnetoelectric effect. Electric current flows through a conductor when magnetic flux changes, typically by moving the conductor through a magnetic field. Various sources of mechanical energy for the required motion are commonly used such as steam (generated by fossil or nuclear fuel), water, compressed air, and wind. Typical electric generators have a rotating part known as the rotor, and a stationary part known as the stator. The conductors are in the form of conductor coils/windings and may be positioned on either the rotor or the stator. Similarly, the magnets that provide the magnetic field (either permanent magnets or electromagnets) may be positioned on either the rotor or the stator.
Because the rotor rotates relative to the stator, electric generators, as with many machines having rotating parts, use bearings between the relatively rotating parts. However, conventional ball bearings have high rotational torque at low rotational speeds and lower rotational torque at high rotational speeds. Frictional heat is generated that can degrade lubricants used with the ball bearings as well as degrading the bearings themselves. Further, at high rotational speeds, ball bearings can vibrate which causes problems at close design tolerances.
Thus there is a need in the art for improved electric generators having improved bearings to ensure smooth operation over a long operating lifetime.